1. Field of the Invention
The present invention relates to a tape cassette such as a video cassette having a double lid structure formed by an outer lid and an inner lid.
2. Description of the Related Art
FIGS. 1A and 1B show a known video cassette in the related art. This video cassette has a cassette body 1 accommodating a magnetic tape 2. The cassette body 1 has a front opening 3 defining a path of the magnetic tape 2 drawn from the cassette body 1. The front opening 3 is adapted to be opened and closed by an outer lid 4 of a single lid structure. A pair of right and left side plates 4a of the outer lid 4 are pivotably connected through a pair of right and left pivot pins 5 to a pair of right and left outside walls 1a of the cassette body 1, respectively. Thus, the outer lid 4 is vertically pivotable about the pivot pins 5 in the opposite directions indicated by arrows a and a', thereby opening and closing the front opening 3. The magnetic tape 2 is adapted to be drawn from the front opening 3 as shown by a two-dot chain line in FIG. 1B.
In this video cassette, the front opening 3 can be sufficiently opened with a small rotational angle of the outer lid 4. That is, as shown in FIG. 1B, a large opening amount H.sub.2 of the front opening 3 can be ensured with a small opening amount H.sub.1 of the outer lid 4. However, no inner lid is provided in the video cassette, so that the magnetic tape 2 in the front opening 3 is not completely enclosed. Accordingly, dust or the like entering through a bottom opening 6 of the cassette body 1 is apt to be attached to the magnetic tape 2, thus reducing the desired dustproof effect.
FIGS. 2A and 2B show another video cassette with an improved dustproof effect and which is known from U.S. Pat. No. 4,449,677. In this video cassette, an inner lid 7 is pivotably connected through a pair of right and left pivot pins 8 to the inside surface of an outer lid 4. A pair of right and left guide pins 9 are formed at the right and left ends of the inner lid 7 on the back side thereof, and a pair of right and left guide grooves 10 are formed in the opposed inside surfaces of a pair of right and left inside walls 1b of a cassette body 1, so as to guide the right and left guide pins 9, respectively. The outer lid 4 is adapted to be pivoted about a pair of right and left pivot pins 5 in the opposite directions of arrows a and a', and the guide pins 9 of the inner lid 7 are adapted to be guided by the guide grooves 10 to move the inner lid 7 together with the outer lid 4 in the directions of the arrows a and a', thereby opening and closing a front opening 3 of the cassette body 1.
As mentioned above, the video cassette shown in FIGS. 2A and 2B has a double lid structure formed by the outer lid 4 and the inner lid 7 to cover both the outside and inside surfaces of a magnetic tape 2 extending across the front opening 3 in the closed condition of the outer lid 4. That is, the magnetic tape 2 extending across the front opening 3 can be completely enclosed in the closed condition of the outer lid 4, thus improving the dustproof effect. However, a relatively large rotational angle of the outer lid 4 is required to raise the inner lid 7 to a sufficiently high level for clearing the tape 2. That is, if an opening amount H.sub.2 of the front opening 3 is to be made equal to that in the video cassette shown in FIGS. 1A and 1B, an opening amount H.sub.1 of the outer lid 4 will have to be considerably larger than that in the video cassette shown in FIGS. 1A and 1B.
A space to be occupied by the video cassette in a VTR is determined by the opening amount H.sub.1 of the outer lid 4. Accordingly, the increase in the opening amount H.sub.1 causes an increase in the occupied space to hinder reduction in the size of the VTR.